RT8251
Layout Consideration
` Connect feedback network behind the output capacitors.
Keep the loop area small. Place the feedback
components near the RT8251.
Follow the PCB layout guidelines for optimal performance
of the RT8251.
` Connect all analog grounds to a command node and
then connect the command node to the power ground
behind the output capacitors.
` Keep the traces of the main current paths as short and
wide as possible.
` Put the input capacitor as close as possible to the device
` Examples of PCB layout guide are shown in Figure 9
pins (VINandGND).
and Figure 10 for reference.
` LX node is with high frequency voltage swing and should
be kept at small area. Keep analog components away
from the LX node to prevent stray capacitive noise pick-
up.
Input capacitor must be placed
as close as to the IC as possible.
C
OUT
C
D
S
GND
C
IN
R
S
L
VOUT
16 15 14 13
SW
SW
SW
VIN
VIN
12
11
10
9
1
2
3
4
SW should be connected
GND
17
to inductor by Wide and
short trace. Keep sensitive
components away from
this trace.
VIN
C
BOOT
BOOT
GND
5
6
7
8
R1
R2
C
SS
R
C
VOUT
C
P
C
C
GND
The feedback components must be connected
as close to the device as possible.
Figure 9. PCB Layout Guide for WQFN Package
Copyright 2013 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
©
DS8251-04 February 2013
www.richtek.com
13
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